Apple Mac OS X Server (Administrator’s Guide) - Manual (Page 68)

68 Chapter 2
Data Consolidation
For years, UNIX systems have stored administrative information in a collection of files located
in the /etc directory. This scheme requires each UNIX computer to have its own set of files,
and processes that are running on a UNIX computer read its files when they need
administrative information. If you’re experienced with UNIX, you probably know about the
files in the /etc directory—group, hosts, hosts.eq, passwd, and so forth. For example, a UNIX
process that needs a user’s password consults the /etc/passwd file, which contains a record for
each user account. A UNIX process that needs group information consults the /etc/group file.
Open Directory consolidates administrative information, simplifying the interactions
between processes and the administrative data they create and use.
UNIX processes
/etc/
passwd
/etc/
hosts
/etc/
group
Mac OS X processes
Directory
services